The Effects of Whole Body Unloading on Physiological Function
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|ClinicalTrials.gov Identifier: NCT03195348|
Recruitment Status : Completed
First Posted : June 22, 2017
Last Update Posted : October 31, 2017
|Condition or disease||Intervention/treatment||Phase|
|Muscle Atrophy Weightlessness Sleep Disturbance Astronaut-Bone Demineralisation Syndrome||Other: HBF Bed Rest||Not Applicable|
Show Detailed Description
|Study Type :||Interventional (Clinical Trial)|
|Actual Enrollment :||12 participants|
|Intervention Model:||Single Group Assignment|
|Masking:||None (Open Label)|
|Official Title:||The Effects of Whole Body Unloading on Physiological Function|
|Actual Study Start Date :||March 29, 2017|
|Actual Primary Completion Date :||August 30, 2017|
|Actual Study Completion Date :||August 30, 2017|
Experimental: HBF Bed Rest
7 days control period followed by a washout period, then 7 days of HBF.
Other: HBF Bed Rest
7 days of bed rest on hyper-buoyancy floatation (HBF)
- Whole body skeletal muscle loss [ Time Frame: 7 days ]The primary aim of this study is to investigate whole body skeletal muscle loss induced through 7 consecutive days of HBF using three independent methods; dual x-ray absorptiometry (DXA), magnetic resonance imaging (MRI) and D3-Creatine dilution (D3-cr)
- Regional differences in muscle loss [ Time Frame: 7 days ]Regional (upper v lower limb) differences in muscle atrophy induced by HBF
- Relationship between change in total skeletal muscle mass and rectus femoris cross sectional area [ Time Frame: 7 days ]To determine the relationship between change in total skeletal muscle mass (measured by MRI) and change in physiological cross sectional area (PCSA) of the rectus femoris as determined by ultrasound measurements of fascicle length and pennation angle.
- Central nervous system changes induced by 7-day HBF [ Time Frame: 7 days ]To use neuroimaging, polysomnography and cognitive battery to investigate any structural (MR brain), neurophysiological (PSG/EEG) and functional (rs-fMRI and CANTAB battery test) central nervous system changes induced by the intervention
- Myofiber cross-sectional area changes with unloading compared with quadriceps cross sectional area [ Time Frame: 7 days ]To determine the change in single muscle fibre cross-sectional area, using immunohistochemical staining, compared to total quadriceps cross-sectional area using ultrasound. Myofiber cross-sectional area will be measured using muscle biopsy tissue which will be mounted onto cork and cut into 5 μm-thick cryosections. Immunohistochemical stainings of muscle tissue cross sections will then measured using a microscope.
- Muscle biochemistry [ Time Frame: 7 days ]To determine the change in biochemical (protein:DNA ratio) markers of quadriceps size in relation to the MRI and ultrasound measurements
- Change in fractional protein synthesis [ Time Frame: 7 days ]To determine the relationship between change in quadriceps skeletal muscle mass (measured by MRI) and change in fractional protein synthesis (FPS) rate measured using tracer (D2O) techniques
- Changes in anabolic and catabolic signalling markers in muscle [ Time Frame: 7 days ]To investigate changes of anabolic and catabolic signalling markers (such as MAFbx/atrogin-1 and MuRF1) in quadriceps muscle after 7 days HBF
- Changes in muscle function [ Time Frame: 7 days ]To measure changes in muscle function as a result of 7 days HBF. These will include maximal voluntary isometric strength of the knee extensors, plantar flexors in the trunk and hand (hand grip) and explosive power during a countermovement jump.
- Changes in cardiorespiratory fitness [ Time Frame: 7 days ]To measure changes in cardio respiratory fitness (maximal aerobic capacity (VO2max)) with 7 days of immobilisation
- Bone mineral density [ Time Frame: 7 days ]To measure changes in bone mineral density (BMD) of before and after a 7 days HBF
- Plantarflexion strength [ Time Frame: 7 days ]To determine the effect of 7 day HBF upon plantar flexion power output using an isokinetic dynamometer
- Muscle tone [ Time Frame: 7 days ]To determine the effect of 7-day HBF upon the viscoelastic properties of superficial muscles and the Achilles tendon using Myoton.The viscoelastic properties of relaxed arm flexor, arm extensor, erector spinae, lateral gastrocnemius and Achilles tendon will be determined at rest (HBF) using the Myoton (hand-held myometer) on day 1, day 3, day 5 and day 7 (last day) of the HBF. This will be done by applying a short (15ms) and almost imperceptible mechanical impulse (force 0.4N) applied directly to the skin. The following parameters are derived from the oscillation acceleration signal generated by the mechanical impulse in real time by the Myoton's software: 1) Dynamic stiffness: which indicates the resistance to deformation of a tissue, 2) Oscillation frequency: which indicates the (muscle) tone or intrinsic tension of a tissue, 3) The logarithmic decrement of the oscillation: which characterises tissue elasticity.
- Functional re-adaptive exercise device (FRED) [ Time Frame: 7 days ]To determine the ability, utility and potential efficacy of FRED following 7 days HBF
To learn more about this study, you or your doctor may contact the study research staff using the contact information provided by the sponsor.
Please refer to this study by its ClinicalTrials.gov identifier (NCT number): NCT03195348
|Sleep Disorders Centre|
|London, United Kingdom|
|Principal Investigator:||Ivana Rosenzweig, PhD||King's College London|